Projector

ABSTRACT

A liquid crystal panel unit is attached to a light incident surface of a prism composite. The liquid crystal panel unit includes a panel frame plate holding a liquid crystal panel, and a fixation frame plate glued and fixed to the light incident surface. The panel frame plate is fastened to the fixation frame plate by screws through an intermediate frame plate. By using wedges, the position of the panel frame plate with respect to the light incident surface is adjusted. This allows the liquid crystal panel to be reliably positioned and fixed so that the deviation amount in pixel matching is minimized and the focus adjustment can be accomplished correctly.

This is a continuation of Ser. No. 08/848,027 filed Apr. 28, 1997, nowU.S. Pat. No. 5,868,485.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a projection type display device whichseparates a white beam from a light source into beams of three colors,i.e., red, blue and green, modulates each color beam through a lightvalve such as a liquid crystal panel in accordance with imageinformation, synthesizes the modulated color beams by light synthesizingmeans, and projects the synthesized beams onto a projection surfacethrough projecting means in an enlarged state. More specifically, theinvention relates to a mechanism for mounting a liquid crystal panel toa prism composite constituting a light synthesizing mechanism of aprojection type display device.

2. Description of Related Art

In a conventional projection type display device, a liquid crystalpanel, serving as a light valve, is mounted to a light incident surfacefor each light beam of a prism composite. The prism composite is a lightsynthesizing mechanism. A conventional mechanism for mounting a liquidcrystal panel to a prism composite is disclosed in Japanese UnexaminedPatent Publication No. 6-118368. In this type of mounting mechanism, theliquid crystal panel, which serves as the light valve, is directly gluedand fixed to the light incident surface of the prism composite by anadhesive.

When the light valve is directly glued and fixed to the light incidentsurface, it is possible to omit the mutual pixel matching mechanism(alignment) of multiple light valves which modulate the light beamseparated into red, green and blue colors. It is also possible to omitthe focus adjusting mechanism (focus adjustment) so that each imageformation plane constituting the subject is positioned within thepermissible depth of focus of the projection lens. Thus, it is possibleto reduce the size, weight and number of parts of the optical system ofthe projection device.

However, when the light valve is directly glued and fixed to the lightincident surface of the prism composite, several problems may arise.These problems are outlined below.

First, when external light enters the interior of the device, there is apossibility that the external light will enter the light valve. When thelight valve receives such light, there is also a possibility of eachelement of the light valve malfunctioning.

Second, directly touching the light valve while treating the light valveis not desirable since that will lead to problems such as breakage. Forexample, when the light valve is glued to the prism composite, chuckingthe light valve directly with a jig may lead to the edge, corner, etc.of the light valve being damaged. Additionally, it is not desirable forthe operator to hold the light valve directly by hand and glue it to theprism composite because the light valve, such as a liquid crystal panel,is also vulnerable to static electricity.

Third, the light valve, which is glued to the prism composite, cangenerate a defect in a part of its pixels as a result of changes withtime. When a defect has been generated in the light valve, it isnecessary to replace it with a new one. However, since the light valveis glued and fixed to the prism composite, it is difficult to replaceonly the light valve having the defect. That is, it is not easy todetach the liquid crystal panel glued and fixed to the light incidentsurface of the prism composite without damaging the light incidentsurface. For this reason, it is necessary in some cases to also replacethe prism composite. The replacement of the prism component, however, isnot economical.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a projection type displaydevice equipped with a light valve mounting mechanism capable of solvingthe above-described problems.

To achieve the above object, the invention is a projection type displaydevice which separates a beam from a light source into a plurality ofbeams of various colors. The projection type display device modulateseach color beam through a light valve in accordance with imageinformation, and thereafter synthesizes the modulated color beams bylight synthesizing mechanisms. The projection type display then projectsthe synthesized beam onto a projection surface, through a projectingmechanism, in an enlarged state. At this point, the periphery of thelight valve is protected against the intrusion of external light,damage, etc. By utilizing this type of projection display, it is notnecessary for the light valve to be directly glued or otherwise fixed tothe light synthesizing mechanism.

In accordance with the invention, the projection type display deviceincludes a fixation frame plate fixed to a light incident surface of thelight synthesizing mechanism. The projection type display furtherincludes a light valve frame plate for holding the light valve, a fixingmechanism for detachably fixing the light valve frame plate to thefixation frame plate, and a positioning mechanism for positioning thelight valve.

Additionally, at least one of the light valve frame plate and thefixation frame plate includes a peripheral wall covering the peripheryof the light valve.

The positioning mechanism may include an adjusting member for adjustingthe position of the light valve. In this case, it is desirable for thelight valve frame plate to be provided with an adjusting member guidingmechanism.

In order for the adjusting member to be easily handled with a jig orsimilar mechanism, it is desirable for the adjusting member to beequipped with at least one engagement section. The engagement sectionwill be utilized when chucking the adjusting member.

Further, it is desirable for the positioning mechanism to be provided inthe vicinity of the center of opposite side portions of the light valveframe plate. This configuration avoids stress concentrations due tothermal deformation of the member constituting the object ofpositioning.

In order for the fixation frame plate and the light valve frame plate tobe easily handled with a jig or similar mechanism, it is desirable forthe fixation frame plate and the light valve frame plate to be equippedwith an engagement section for chucking the plates.

In addition to the fixation frame plate and the light valve frame plate,an intermediate frame plate is disposed between the fixation frame plateand the light valve frame plate. In this case, the intermediate frameplate is fixed to the fixation frame plate by the fixing mechanism. Theintermediate frame plate is further fixed in a certain position on thelight valve frame plate by the positioning mechanism.

In this case, a temporal fixing mechanism is provided for temporarilyfixing the intermediate frame plate and the light valve frame plate. Itis desirable that the intermediate plate, temporarily fixed by thetemporal fixing mechanism and the light valve frame plate, be positionedby the positioning mechanism. This makes it possible to perform thetemporal fixing operation in the temporarily fixed state, therebyallowing the positioning operation to be easily performed.

The temporal fixing mechanism may include an engagement protrusionformed on either the intermediate frame plate or the light valve frameplate. An engagement hole will be formed in the plate that does notinclude the engagement protrusion. In this case, the plates can betemporarily fixed by an adhesive.

Even in the case in which an intermediate plate is provided, thepositioning mechanism may include adjusting parts for adjusting theposition of the light valve. Further, the light valve frame plate may beprovided with an adjusting member guiding mechanism. The adjusting partsmay be equipped with at least one engagement section used when chuckingthe adjusting member. The positioning mechanism may be provided in thevicinity of the center of opposite side portions of the light valveframe plate.

In accordance with the invention, the light valve may be placed betweenthe light valve frame plate and the fixation frame plate.

In accordance with the above-described projection type display device,the light valve is held by the light valve frame plate. Further, thefixation frame plate is fixed to the light incident surface of the lightsynthesizing mechanism, and the light valve frame plate, holding thelight valve, is detachably fixed to the fixation frame plate. This canbe accomplished directly or through the use of the intermediate frameplate.

Thus, when a defect is generated in the light valve as a result ofchange with time, the light valve frame plate holding the light valve isdetached from the fixation frame plate which is fixed to the lightsynthesizing mechanism. At this time, a light valve frame plate whichholds a new light valve is mounted to the fixation frame plate. In thisway, the light valve is not directly fixed to the light synthesizingmechanism, so that the light valve can be replaced easily. Further, whenperforming the replacing operation, the surface of the lightsynthesizing means is not damaged.

In accordance with the projection type display device, the periphery ofthe light valve is protected by the light valve frame plate. Thispermits the light value to be mounted to the light synthesizingmechanism without directly touching the light valve. Thus, it ispossible to prevent the light valve from being damaged. Further, byusing the above configuration, no external light enters the inventionwhich would cause a malfunction, because its periphery is covered withthe light valve frame plate.

A liquid crystal device may be used as the above-mentioned light valve.Further, the invention is particularly effective in the case of a liquidcrystal device which is vulnerable to static electricity and which maycause a malfunction when external light strikes the liquid crystaldevice.

Further, the light valve can be classified into a light transmissiontype and a light reflection type. When a light reflection type lightvalve is used, the light synthesizing mechanism may also serve as alight separation mechanism for separating a beam from the light sourceinto a plurality of beams of various colors.

Two types of projection type display devices are also contemplated.These projections type display devices include a front surfaceprojection type display device and a back surface projection typedisplay device. The projection of the front surface projection typedisplay device is effected from the side on which the projection surfaceis observed, and the projection of the back surface projection typedisplay device is effected from the side opposite to the side on whichthe projection surface is observed. The invention is applicable to bothtypes.

When a dichroic prism is used as the light synthesizing mechanism, thelight valve is positioned and fixed to the surface of the dichroic prismby using a fixation frame plate, a light valve frame plate, a fixingmechanism and a positioning mechanism. The fixing structure may beapplied to a structure such as a camera in which a solid-state imagesensing device such as CCD is positioned and fixed to a color separationprism.

Further objects, details and advantages of the invention will beapparent from the following detailed description, when read inconjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a projection type display device inaccordance with the invention.

FIG. 2(A) is an elevational view of components in the interior of thedevice of FIG. 1.

FIG. 2(B) shows an elevational view of the components of the device.

FIG. 3(A) shows an optical unit and a projection lens unit.

FIG. 3(B) is a schematic showing the optical system.

FIG. 4 is a partial perspective view showing a head plate, a prism unitand a liquid crystal panel unit.

FIG. 5 is an exploded perspective view of the liquid crystal panel unitof FIG. 4.

FIG. 6 is an exploded perspective view of a first modification of theliquid crystal panel unit of FIG. 5.

FIG. 7 is an exploded perspective view of a second modification of theliquid crystal panel unit of FIG. 5.

FIG. 8 is an exploded perspective view of another embodiment of theliquid crystal panel unit.

FIG. 9 is a perspective view of a modification of the first fixationframe plate of FIG. 8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Overall Construction of the Device

FIG. 1 shows a perspective view of a projection type display device 1.The projection type display device 1 of this example has a substantiallyrectangular parallelopiped case 2. The case 2 basically includes anupper case 3, a lower case 4 and a front case 5 defining a front face ofthe device. The forward end portion of a projection lens unit 6protrudes from the center of the front case 5.

FIG. 2 shows the arrangement of components inside the case 2 of theprojection type display device 1. As shown, a power source unit 7 islocated at the rear end of the interior of the case 2. A light sourcelamp unit 8 and an optical unit 9 are located proximate the front sideof the case 2. A base end of a projection lens unit 6 is located at thecenter of the front side of the optical unit 9. An interface board 11 isdisposed on one side of the optical unit 9. The interface board 11 hasan input/output interface circuit mounted thereon. The interface board11 is arranged to extend in the longitudinal direction of the device. Avideo board is disposed parallel to the interface board. A video signalprocessing circuit is mounted on the video board. A control board 13,for device drive control, is placed above the light source lamp unit 8and the optical unit 9. Speakers 14R and 14L are located in the rightand left corners of the front side of the device, respectively.

An intake fan 15A for cooling is located at the center of the upper sideof the optical unit 9. A circulation fan 15B is located at the center ofthe bottom side of the optical unit 9. The circulation fan 15B forms acirculation flow for cooling the device. An air discharge fan 16 issubstantially behind the light source lamp unit 8. Proximate to thepower source unit 7 and facing the ends of the boards 11 and 12, is anauxiliary cooling fan 17 for sucking the cooling air flow from theintake fan 15A into the power source unit 7. Directly above the powersource unit 7 is a floppy disk driving unit 18. In the preferredembodiment, the power source unit is positioned on the left side of thedevice.

Optical Unit and Optical System

FIG. 3(A) shows a portion of the device corresponding to the opticalunit 9. As shown in FIG. 3(A), the optical unit 9 has optical elementsincluding a prism unit 20. The optical elements, which constitute itscolor synthesizing mechanism 15, are placed between upper and lowerlight guides 901 and 902. The upper and lower light guides 901 and 902are fixed to the upper case 3 and the lower case 4 by fixing screws,respectively. The upper and lower light guides 901 and 902 are fixed tothe side of the prism unit 20 by fixing screws.

The prism unit 20 is fixed to the back side of a thick head plate 30 byfixing screws. In the preferred embodiment, the thick head plate 30 is adie-cast plate. The base side of the projection lens unit 6 is fixed tothe front side of this head plate 30 by fixing screws. The projectionlens unit 6 serves as the projection mechanism. Thus, in this example,the prism unit 20 and the projection lens unit 6 are fixed together withthe head plate 30 therebetween. Thus, even if an impact is applied tothe side of the projection lens unit 6, no positional deviation isgenerated in these two components.

FIG. 3(B) schematically shows the optical system of the projection typedisplay device 1. The optical system of this example includes a lightsource lamp 805 and an illumination optical system 923. The illuminationoptical system 923 includes integrator lenses 921 and 922. Theintegrator lenses 921 and 922 are uniform illumination optical elements.A color separation optical system 924 for separating a white beam Woutput from the illumination optical system 923 into color beams of red,green and blue, i.e., R, G and B, respectively, is also provided. Theoptical system further includes three liquid crystal panels 40R, 40G and40B, which serve as light valves for modulating the color beams, and aprism composite 20. The prism composite 20 serves as a colorsynthesizing optical system for synthesizing the modulated color beams.Additionally, a projection lens unit 6, for projecting the synthesizedbeam onto a projection surface 7 in an enlarged state, is also provided.A light guide system 927 for guiding the blue color beam B of the colorbeams separated by the color separation optical system 924 to thecorresponding liquid crystal panel 40B is also provided.

The light source lamp 805 may include a halogen lamp, a metal halidelamp, a xenon lamp or other light sources. The uniform illuminationoptical system 923 is equipped with a reflection mirror 931. Thereflection mirror 931 bends the optical axis 1a of the beam output fromthe illumination optical system by 90°. This allows the output to begenerated towards the forward portion of the device. The integratorlenses 921 and 922 are arranged so as to be orthogonal to each otherwith the reflection mirror 931 placed therebetween.

The color separation optical system 924 includes a blue/green reflectiondichroic mirror 941, a green reflection dichroic mirror 942 and areflection mirror 943. The blue beam B and the green beam G, containedin the white beam W, are reflected at right angles by the blue/greenreflection dichroic mirror 941 and directed toward the green reflectiondichroic mirror 942. The red beam R is transmitted through theblue/green reflection dichroic mirror 941 and reflected at a right angleby the reflection mirror 943. The red beam R is then reflected to theprism composite 20 from an output section 944 for the red beam. Only thegreen beam G is reflected at right angles by the green reflectiondichroic mirror 942 and output to the color synthesizing optical systemfrom an output section 945 for the green beam. The blue beam B, which istransmitted through the green reflection dichroic mirror 942, is outputto the light guide system from an output section 946 for the blue beam.In this example, the distances from the output section for the whitebeam of the uniform illumination optical elements to the output sections944, 945 and 946 for the color beams in the color separation system 924are all set to the same distance.

Condenser lenses 951 and 952 are arranged on the output sides of theoutput sections 944 and 945 for the color beams of the color separationsystem 924, respectively. Thus, the color beams output from the outputsections incident upon these condenser lenses 951 and 952 are turnedinto parallel beams. The parallel color beams R and G, which areincident upon the liquid crystal panels 40R and 40G, are then modulated.Thereafter, image information corresponding to each color beam is addedthereto. That is, the liquid crystal panels 40R and 40G undergoswitching control in response to image signals corresponding to imageinformation. This is accomplished by a driving mechanism (not shown),whereby the color beams passing therethrough are modulated. Any knowndriving mechanism may be used.

The blue beam B is guided to the corresponding liquid crystal panel 40Bthrough the light guide system 927. The blue beam B is similarlymodulated in accordance with image information. The liquid crystalpanels 40R, 40G and 40B used in this example may include, for example,poly-silicon-TFT used as switching elements.

The light guide system 927 has an input side lens 954, an input sidereflection mirror 971, an output side reflection mirror 972, anintermediate lens 973, and the condenser lens 953. The intermediate lens973 is located between the input side reflection mirror 971 and theoutput side reflection mirror 972. The condensor lens 953 is located infront of the liquid crystal panel 40B. The blue beam B has the longestoptical path length of the color beams, i.e., the distance from thelight source lamp 805 to the respective liquid crystal panel. Thus, thelight quantity loss of the blue beam B is the greatest. However, thelight quantity loss can be restrained due to the light guide system 927.Thus, it is possible to make the optical path lengths of the color beamssubstantially equivalent to each other.

Next, the color beams are modulated by passing through the liquidcrystal panels 40R, 40G and 40B incident upon the prism composite 22, atwhich time they are synthesized. In this example, the prism composite 22that includes a dichroic prism is used to form the color synthesizingoptical system. Color images synthesized at this point are projected inan enlarged state onto a projection surface 7, which is disposed at apredetermined position. This is accomplished utilizing the projectionlens unit 6.

Construction of Prism Unit and Head Plate

FIG. 4 shows a head plate 30. Attached to the head plate 30 is the prismunit 20. The head plate 30 includes a widthwise vertical wall 31 and ahorizontal bottom wall 32 extending from the lower end of the verticalwall 31. The vertical wall 31 has a rectangular opening 31b throughwhich the output beam from the prism unit 20 is transmitted. A number ofreinforcing ribs are formed on the vertical wall 31 to enhance itsrigidity. The prism unit 20 and the projection lens unit 6 are alignedand secured in position with the vertical wall 31 placed therebetween(See FIG. 3(A)). These components are firmly connected, thus eliminatingthe possibility that a mutual positional deviation can occur, even if animpact or similar operation is applied to them.

The prism unit 20 is disposed on the upper surface of bottom wall 32 ofthe head plate 30. The prism unit 20 is equipped with a rectangularparallelopiped prism composite 22 formed by joining together the slantfaces of four prisms 21 and a prism support plate 33. Each of the fourprisms 21 have a right-angled isosceles triangle (See FIG. 5) sectionalconfiguration. The bottom portion of the prism composite 22 is fixed tothe surface of the prism support plate 33 by adhesion or the like. Theprism support plate 33 is mounted on and fixed to the bottom wall 32 ofthe head plate. Liquid crystal panel units 50R, 50G and 50B, of the sameconstruction, are mounted to the three side surfaces of the sidesurfaces of the prism composite 22. The side surfaces function as lightincident surfaces. Liquid crystal panels 40R, 40G and 40B are held bythe liquid crystal panel units 50R, 50G and 50B, respectively.

Liquid Crystal Panel Mounting Structure

FIG. 5 is an exploded view showing components of the liquid crystalpanel unit 50R. The liquid crystal panel unit 50R holds the liquidcrystal panel 40R. FIG. 5 shows the mounting structure for mounting theliquid crystal panel 40R to the prism composite 22.

As shown in FIG. 5, the liquid crystal panel unit 50R is equipped with apanel frame plate 51 for holding the liquid crystal panel 40R. The panelframe plate 51 includes a first frame plate 52 and a second frame plate53. The liquid crystal panel 40R is held between frame plates 52 and 53.

The liquid crystal panel unit 50R is further equipped with a fixationframe plate 54 which is glued or otherwise fixed to the light incidentsurface 22R of the prism composite 22. The panel frame plate 51 isdetachably attached to a side of the fixation frame plate 54 by anintermediate plate 55.

The panel frame plate 51 includes a first frame plate 52. The firstframe plate 52 is equipped with a rectangular opening 52a fortransmitting light and a peripheral wall 52b with a uniform thickness.The second frame plate 53 also has a rectangular opening 53a fortransmitting light. The size of the second frame plate 53 is slightlysmaller than the first frame plate 51, thus allowing it to be fitted inthe inner side of the peripheral wall 52b. An engagement protrusion 53cis formed at the center of each of the right and left edges of thesecond frame plate 53. An engagement groove 52c, in which the engagementprotrusion 53c is fitted, is formed at the center of each of the rightand left outer sides of the peripheral wall 52b. The panel frame body 51is formed when the first and second frame plates 52 and 53 aresuperimposed upon one another. The liquid crystal panel 40R is placedtherebetween. At this time, the engagement protrusions 53c are fittedinto the engagement grooves 52c. The liquid crystal panel 40R sitsbetween the frame plates 52 and 53.

An intermediate frame plate 55 is a rectangular frame substantially thesame size as, or slightly larger than, the first frame plate 52. Theintermediate frame plate 55 is equipped with a rectangular opening 55afor transmitting light. Engagement protrusions 55d extendperpendicularly from the surface of the frame plate 55, and areproximate to the four corners of the rectangular opening 55a of theintermediate frame plate 55. The first frame plate 52 of the panel frameplate 51 has engagement holes 52d corresponding to the engagementprotrusions 55d. The engagement protrusions can be inserted into theengagement holes 52d. A temporarily fixed condition is accomplished whenthe panel frame plate 51 and the intermediate frame plate 55 aresuperimposed upon one another with the engagement holes 52d and theengagement protrusions 55b being engaged. It is at this time that theengagement protrusions 55d are inserted into the engagement holes 52d.

The fixation frame plate 54 is also a rectangular frame plate having arectangular opening 54a for transmitting light. The back surface of thefixation frame plate 54 is fixed to the light incident surface 22R ofthe prism composite 22 by an adhesive. Screw holes 54c are formed in theright and left upper corners of the fixation frame plate 54. Screw holes55c corresponding to the screw holes 54c are formed in the intermediateframe plate 55.

A protruding frame 54b that protrudes toward the intermediate frameplate 55 is formed in the lower frame section of the fixation frameplate 54. A protruding frame 55b, into which the protruding frame 54b isto be fitted from the back side, is formed in the lower frame section ofthe intermediate frame plate 55. The panel frame plate 51 is held bybeing placed on the protruding frames 54b and 55b. The protruding frames54b and 55b have right and left screw holes 54e and 55e.

In this way, screw holes 54c, 54e and 55c, 55e are formed at mutuallycorresponding positions of the fixation frame plate 54 and theintermediate frame plate 55. These frame plates are fastened together byfour flat countersunk head screws 56, one of which is shown in FIG. 5,which are threadedly engaged with the corresponding screw holes. Thatis, the intermediate frame plate 55 is screwed to the fixation frameplate 54 and glued to the prism composite 22.

The liquid crystal panel unit 50R is equipped with four wedges 57serving as a positioning mechanism. FIG. 5 shows only one of thesewedges. Wedge guide surfaces 52e are formed in the right and leftsections of the peripheral wall of the first frame plate 52 of the panelframe plate 51. After temporarily fixing the panel frame plate 51 to theintermediate frame plate 55, the four wedges 57 are inserted into theright and left sides of the first frame plate 52. The insertion depth ofthese wedges 57 is adjusted, so that the liquid crystal panel 40R can beadjusted.

The liquid crystal panel unit 50R is mounted to the light incidentsurface 22R of the prism composite 22. This mounting is accomplished byfirst preparing the panel frame plate 51 holding the liquid crystalpanel 40R. Next, the fixation frame plate 54 is positioned on the face22R of the prism composite 22 and is glued and fixed thereto. Theadhesive used may be an ultraviolet setting type adhesive or similaradhesive. Thereafter, the intermediate frame plate 55 is positioned onthe surface of the fixation frame plate 54.

The intermediate frame plate 55 is then glued and fastened thereto bythe four screws 56. After this, the panel frame plate 51 holding theliquid crystal panel 40R is positioned on the intermediate frame plate55 and temporarily fixed thereto. That is, the engagement protrusions55d of the intermediate frame plate 55 is aligned with respect to theengagement holes 52d of the panel frame plate 51. After alignment, thepanel frame plate 51 is pushed toward the intermediate frame plate 55.It becomes easier to achieve a high level of positional accuracy whenthe fixation frame plate 54 and the intermediate frame plate 55 areconnected to each other by the screws 56 before gluing and fixing thefixation frame plate 54 to the prism composite 22.

After this, the liquid crystal panel 40R is positioned with respect tothe face 22R of the prism composite 22 by using wedges 57. The wedges 57serve as a positioning mechanism. That is, the four wedges 57 areinserted into a gap between the panel frame plate 51 and theintermediate frame plate 55. The wedges are temporarily fixed to eachother along the wedge guide surfaces 52e formed on the first frame plate52. Then, by adjusting the insertion amount of the wedges 57, thealignment and focus adjustment of the liquid crystal panel 40R areaccomplished.

When the positioning has been achieved, the wedges 57 are glued andfixed to the panel frame plate 51 and the intermediate frame plate 55,which is the object of positioning, by using an adhesive. The adhesiveused may be an ultraviolet setting type adhesive.

The positioning of the wedges 57 and the gluing and fixing of the wedges57 is described in more detail. First, the focusing plane of the liquidcrystal panel 40G is set in the focusing plane of the projection lens 6by using a dedicated adjusting device. In this condition, the engagementprotrusions 55d of the intermediate plate 55 are inserted into theengagement holes 52d of the light valve frame plate 51. This defines agap into which an ultraviolet setting type adhesive is injected.Temporal fixation is caused by ultraviolet radiation. Next, ultravioletradiation is used on the ultraviolet setting type adhesive from theexposed end surfaces of the wedges 57 to cause final fixation. This isperformed near the intermediate frame plate 55 and the wedge guidesurfaces 52e formed on the first frame plate 52. By using the liquidcrystal panel 40G arranged at the center of the liquid crystal panels40G, 40R and 40B as a reference, focusing adjustment and mutual pixelmatching adjustment are accomplished on the liquid crystal panels 40Rand 40B. Temporal fixation and final fixation are then accomplished.

Since the temporal fixation is performed by setting the components in anadjusting device, with the prism composite 22 and the projection lens 6mounted on the head plate 30, an optimum adjustment adapted to thecharacteristics of each component is possible. Further, the chucking ofthe light valve frame plate 51 in the adjusting device is conducted byusing the outer configuration of the first frame plate 52a.

The liquid crystal panel units 50G and 50B holding the liquid crystalpanels 40G and 40B have the same structure as liquid crystal plan unit50R. Thus, a description of liquid crystal panel units 50G and 50B isomitted.

In this way, the liquid crystal panel units 50R, 50G and 50B areattached to the three surfaces 22R, 22B and 22G of the prism composite22, respectively. This results in the structure shown in FIG. 4. In FIG.4, the components extending upwards from the liquid crystal panel units50R, 50G and 50B are flexible cables 41R, 41G and 41B, respectively, forwiring.

The liquid crystal panel unit 50R described above provides severaladvantages. First, the periphery of the liquid crystal panel 40R iscovered with and protected by the rectangular panel frame plate 51.Thus, there is no need to directly touch the liquid crystal panel 40Rwhen mounting it to the prism composite 22. As a result, it is possibleto prevent the liquid crystal panel from being touched by other parts,thereby eliminating the possibility of breakage or damage. Further,since the periphery of the liquid crystal panel 40R is covered with theframe plate 51, it is possible to intercept external light. Thus, evenif external light is allowed to intrude, no malfunction occurs in theliquid crystal panel 40.

Second, the panel frame plate 51, holding the liquid crystal panel 40R,is detachably fastened by screws to the face 22R of the prism composite22 through the intermediate frame plate 55. Thus, when a defect isgenerated in the liquid crystal panel 40R, it can be replaced by simplydetaching the screws 56. Further, since the liquid crystal panel 40R isnot directly glued or otherwise fixed to the prism composite 22, thereis no concern that the sides of the prism composite 22 will be damaged.Thus, it is possible to use expensive parts without wasting them.

Third, the panel frame member 51 holding the liquid crystal panel 40Rcan be temporarily fixed to the intermediate frame plate 55. Afterachieving the temporarily fixed state, the liquid crystal panel 40R canbe positioned with respect to the face 22R of the prism composite 22. Inthis way, a temporarily fixed state is accomplished so that thepositioning operation using the wedges 57 is easily conducted. Due tothis advantage, improvement can be achieved in terms of the cycle timeof the equipment.

Here, the wedges 57 may generally be formed of glass. However, when thefirst frame plate 52 is formed of a resin, its coefficient of thermalexpansion is larger than that of glass. Due to the difference in thermalexpansion, the wedges 57 may separate from the frame plates or bedamaged as a result of changes in temperature. To avoid this, it isdesirable for the wedges 57 to be formed of a resin, such as an acrylicresin. By forming the wedges 57 of an acrylic material, molding is alsopossible. This substantially reduces the costs as compared to the casein which glass material is used. Additionally, by using a material whichallows transmission of ultraviolet rays as the material of the wedges57, it is possible to use an ultraviolet setting type adhesive. Thisprocess involves a minimal rise in temperature and requires a short timefor curing.

Further, as a result of the formation of the wedge guide surfaces 52e onthe first frame plate 52, upper and lower end surfaces 52f and 52g areformed. The wedges 57 are guided by these three surfaces. That is, whenthis portion is filled with adhesive and then the wedge 57 is inserted,the wedge 57 is automatically led to the interior while being guided bythese three surfaces. This is mainly due to the surface tension of theadhesive. Thus, an improvement is achieved in terms of resistance todisturbances experienced during the process as well as facilitating themounting of the wedges 57.

While in this example an adhesive is used for the temporal fixation ofthe panel frame plate 51 to the intermediate frame plate 55, solderingor a similar technique can be used for this purpose. When the firstframe plate 52, etc. are formed of resin, a metal member may be attachedto the joint section of engagement holes 52d and engagement protrusions55d. Alternatively, a metalization layer may be formed in the jointsection of engagement holes 52d and engagement protrusions 55d.

Next, the first frame plate 52, the intermediate frame plate 55 and thefixation frame plate 54 may include a molded product of a thermosettingresin mixed with glass fiber or calcium carbonate. When such a resinmaterial is used, its coefficient of thermal expansion becomes closer tothat of glass as compared with ordinary resin materials. Thus, in thecondition in which it is attached to the prism composite 22, pixeldeviation or similar problems attributable to thermal deformation can beavoided.

While it is possible, as described above, to use an ultraviolet settingtype adhesive as the adhesive for gluing and fixing the fixation frameplate 54 to the prism composite 22, it is desirable to apply a groundsurface processing material to achieve a higher level of adhesiveness.That is, in the prism composite 22, the incident surface 22R for the redbeam and the incident surface 22B for the blue beam are opposed to eachother, as described above. A part of the blue beam may be transmittedthrough the reflection layer of the prism composite 22 to reach theincident surface 22R for the red beam on the opposite side. Amalfunction may occur when such a transmitted beam is allowed toincident upon the liquid crystal panel 40R. To avoid this malfunction, afilter is attached to the incident surface 22R for the red beam tointercept such transmitted beam.

A filter is only attached to the incident surface 22R for the red beambecause the influence of the transmitted beam of the blue beam, whichhas the shortest wavelength among three color beams, is the mostsignificant. When the influence of such a transmitted beam of some othercolor beam is significant, a filter may be provided on a surface otherthan the surface 22R, or a plurality of filters may be provided on aplurality of surfaces.

However, when such a filter exists, the ultraviolet radiation applied atthe time of gluing and fixing may be intercepted. This may result insome portions of the ultraviolet setting type adhesive for gluing andfixing the fixation frame plates 54 to the incident surfaces 22R, 22Gand 22B of the prism composite 22 not being sufficiently irradiated withultraviolet rays. To avoid this problem and reliably glue or otherwisefix the fixation frame plate 54 to the incident surface 22R, it isdesirable, as described above, to apply a ground surface processingmaterial to these adhesion surfaces preferably using an anaerobic typeadhesive. A is similar processing can occur without a filter.

While in the above description an ultraviolet setting type adhesive isused, it is also possible to use other types of adhesives. For example,when a hot-melt type adhesive is used for the gluing and fixation of thefixation frame plate 54 and the wedges 57, there is no need to take intoaccount the above problem due to the filter.

First Modification of the Liquid Crystal Panel Unit

As shown in FIG. 6, when there is no need to temporarily fix the panelframe member 51 to the intermediate frame plate 55, the temporalfixation mechanism formed between the panel frame member 51 and theintermediate frame plate 55 can be omitted. That is, the engagementholes 52d formed on the panel frame plate 51 side and the engagementprotrusions 55d formed on the intermediate frame plate 55 side can beomitted. In this case, the panel frame member 51 is fixed to theintermediate frame member 55 solely by the wedges 57.

Also, when a liquid crystal panel unit 500R as shown in FIG. 6 is used,it is possible to obtain the above first and second effects achieved bythe liquid crystal panel 50R. Further, it is effective in reducing thesize of the prism unit 20.

Second Modification of the Liquid Crystal Panel Unit

FIG. 7 is an exploded view of a liquid crystal panel unit 70R accordingto a second modification of the liquid crystal panel unit 50R. Thecomponents corresponding to those of the liquid crystal panel unit 50Rshown in FIG. 5 are indicated by the same reference numerals, and adescription thereof is omitted.

As shown in FIG. 7, the liquid crystal panel unit 70R is equipped with apanel frame plate 71 for holding the liquid crystal panel 40R. Like thepanel frame plate 51 of the liquid crystal panel unit 50R, this panelframe plate 71 is equipped with first and second frame plates 72 and 73.The liquid crystal panel 40R is placed and held between these frameplates. FIG. 7 only shows the first frame plate 72. The second frameplate 73 and the liquid crystal panel unit 40R are already mounted andfixed to the first frame plate 72 side. The liquid crystal panel unit70R is further equipped with a fixation frame plate 74 glued and fixedto the light incident surface 22R of the prism composite 22. The panelframe plate 71 is detachably attached to this fixation frame plate 74 byan intermediate frame plate 75.

The panel frame plate 71 is similar to the above-described panel frameplate 51 of the liquid crystal panel unit 50R. The first frame plate 72is equipped with a rectangular opening 72a for transmitting light and aperipheral wall 72b having a fixed thickness. The second frame plate 73also has a rectangular opening (not shown) for transmitting light. Thesize of this second frame plate 73 allows it to be fitted into the innerside of the peripheral wall 72b. Thus, the panel frame plate 71 isformed when the second frame plate 73 is fitted into the first frameplate 72 with the liquid crystal panel 40R being placed between thefirst and second frame plates 72 and 73. In this configuration, theliquid crystal panel 40R is held between the frame plates 72 and 73.

The fitting structure for the first frame plate 72 and the second frameplate 73 is substantially similar to the first and second frame plates52 and 53 of the panel frame plate 51 shown in FIG. 5. However, in thecase of this example, hooks and engagement grooves, to be engaged withthe hooks, are formed at upper and lower positions with guide grooves72e-72g of the first frame plate 72 therebetween. These sections areomitted in the drawing.

The intermediate frame plate 75 is substantially the same size as thefirst frame plate 72 of the panel frame plate 71. The intermediate frameplate is equipped with a rectangular opening 75a for transmitting light.The intermediate frame plate 75 includes a rectangular opening 75ahaving four corners. Engagement protrusions 75d extendingperpendicularly from the surface of the frame plate are contemplatedproximate to each of the four corners. At the corresponding positions onthe first frame plate 72 of the panel frame plate 71, are engagementholes 72d into which these engagement protrusions are inserted. Theengagement holes 72d engage the engagement protrusions 75b when thepanel frame plate 71 and the intermediate frame plate 75 aresuperimposed upon one another. A temporarily fixed state is achieved atthis time.

The fixation frame plate 74 is also a rectangular frame plate having arectangular opening 74a for transmitting light. The back side of thefixation frame plate 74 is fixed to the light incident surface 22R ofthe prism composite 22 by means of an adhesive. Screw holes 74c areformed in both corners of the upper frame portion of the fixation frameplate 74 and at the center with respect to the horizontal direction ofthe lower frame portion of the fixation frame plate 74. Screw holes 75ccorresponding to three screw holes 74c are formed in the intermediateframe plate 75. The intermediate frame plate 75 is fastened to thefixation frame plate 74 by fastening flat countersunk head screws 76into the corresponding screw holes 74c and 75c. In this example, theintermediate frame plate 75 is fixed to the fixation frame plate 74 bythree screws 76. The number of screws may be four, as shown in FIG. 5.Alternatively, more than 5 screws may also be used. Generally, thesmaller the number of screws, the smaller the number of screwingprocesses.

Engagement protrusions 74 are formed in the right and left corners ofthe lower frame portion of the fixation frame plate 74. Engagement holes75b corresponding to the two engagement protrusions 74b are formed inthe corresponding right and left corners of the lower frame portion ofthe intermediate frame plate 75. Thus, the engagement holes 75b of theintermediate frame plate 75 are matched with the engagement protrusions74b of the fixation frame plate 74. The intermediate frame plate 75 isalso pushed toward the fixation frame plate 74, whereby the intermediateframe plate 75 can be temporarily attached to the fixation frame plate74. This makes it possible to further improve the positioning accuracyfor these frame plates.

The liquid crystal panel unit 70R of this embodiment is also equippedwith a positioning mechanism. The positioning mechanism positions thepanel frame plate 71 with respect to the intermediate frame plate 75which is also fixed to the fixation frame plate 74. This positioningmechanism is equipped with two wedges 77. Guide surfaces 72e-72g,against which the slant faces of the wedges 77 abut, are formed at thecenter with respect to the vertical dimension of the right and left sidesurfaces of the peripheral wall 72a of the first frame plate 72 of thepanel frame plate 71. When the panel frame plate 71 is temporarily fixedto the intermediate frame plate 75, wedge insertion grooves are formedbetween the wedge guide grooves 72e of the first frame plate 72 and theframe portion of the intermediate frame plate 75 opposite thereto. Thus,after temporarily fixing the panel frame plate 71 to the intermediateframe plate 75, the two wedges 77 are fitted into the right and leftsides of the first frame plate 72. The insertion amount of each of thesewedges 77 is adjustable, to position the liquid crystal panel 40R. Theprocess for forming the prism unit 20 is the same as that in theabove-described example, so that a description thereof is omitted.

The liquid crystal panel unit 70R as described above also provides thesame effect as the liquid crystal panel unit 50 shown in FIG. 5.

Further, unlike the cases shown in FIGS. 5 and 6, this example adoptsframe plates having a flat configuration as the fixation frame plate 74and the intermediate frame plate 75. As described with reference to FIG.2(B), a fan 15B is arranged underneath the prism composite 22 andcooling air flows upwards from below. To prevent disturbance of this airflow, it is desirable to arrange a flow regulating plate at a positionabove the fan 15B. Since the fixation plate 74 and the intermediateframe plate 75 are flat plates, it is possible to extend the mountingposition for the flow regulating plate to a position directly below theliquid crystal panel 70R. Thus, it is possible to effectively cause thecooling air to flow from below towards the upward portion of the device.Further, since the configuration of these frame plates is simple, themachining of the parts is easy to accomplish. This, in turn, providesfor an improvement in parts accuracy.

Additionally, in the liquid crystal panel unit 70, two wedges 77 forpositioning are used. The wedges 77 are mounted to the central positionswith respect to the vertical dimension of the right and left sides ofthe first frame plate 72 and the intermediate frame plate 75. It isglued and fixed at this position. When the wedges 77 are notappropriately positioned, an excessive concentration of stress may begenerated in the components due to thermal deformation of the firstframe plate 75, the intermediate frame plate 75 or the wedges 77. Thereis also a concern that the wedges 77 may be separated from the firstframe plate 72 or the intermediate frame plate 75. However, as describedabove, the wedges 77 are glued and fixed to the central positions of theright and left sides. As such, the first frame plate 75 and theintermediate frame plate 75 can freely undergo thermal deformation inthe vertical direction around these portions. Thus, the degree ofconstraint of thermal deformation of these frame plates is low, therebyavoiding problems such as an undesirable concentration of stress orseparation of the wedges.

Further, as shown in FIG. 7, each of the wedges 77 of this example hastwo blind holes 77c on the back surface 77b thereof. These blind holesserve as engagement sections for chucking when the wedges 77 are chuckedby using a jig. By forming these blind holes 77c, the chucking isfacilitated. Thus, the handling of the wedges is facilitated.

In this example, blind holes 77c for engagement at the time of chuckingare formed on the back side of the wedges 77. However, the engagementsections for chucking may be formed on other components. For example,engagement sections for chucking, such as blind holes, may be formed onthe outer surface of the peripheral wall 72a of the panel frame plate71.

FIG. 8 shows another embodiment of the liquid crystal panel unit. Aliquid crystal panel unit 60R shown in this embodiment has a panel frameplate 61 for holding the liquid crystal panel 40R and a fixation frameplate 64 which is glued and fixed to the surface 22R of the prismcomposite 22. However, there is no portion corresponding to theintermediate frame plate 55 as in the above-described examples. Thus,the panel frame member 61 is directly screwed to the fixation frameplate 64.

FIG. 8 shows that the structure of the panel frame plate 61 is the sameas the structure of the panel frame plate 51 of FIG. 5. The panel frameplate 61 is equipped with a first frame plate 62 and a second frameplate 63, with the liquid crystal panel 40R being placed therebetween.To keep these first and second frame plates 62 and 63 engaged,engagement hooks 63c and engagement claws 62c are used. These first andsecond frame plates 62 and 63 have rectangular openings 62a and 63a fortransmitting light.

The fixation frame plate 64, on the other hand, has a holder in theperiphery of the rectangular frame portion, i.e., a peripheral wall 64eof a fixed width. The panel frame plate 61 can be fitted into theinterior of the peripheral wall 64e. Further, screw holes 64f are formedin the four corners of the inner periphery of the peripheral wall 64e.Screw holes 62f corresponding to the screw holes 64f are formed in thefour corners of the first frame plate 62 of the panel frame plate 61. Bythreadedly engaging screws 66 with these screw holes, the panel frameplate 61 is fastened to the fixation frame plate 64.

Upper and lower wedge guide surfaces 64g are formed on one side surfaceof the peripheral wall 64e of the fixation frame plate 64. On the otherside surface, a wedge guide surface 64g is formed at a central positionwith respect to the vertical dimension.

The liquid crystal panel unit 60R described above is formed by fixingthe panel frame plate 61 to the fixation frame plate 64 by screws 66.After this, the positioning with respect to the surface 22R of the prismcomposite 22 is accomplished. In this condition, three wedges 67 areinserted into the wedge guide surfaces 64g. The positioning ismaintained such that the gap is reduced to zero due to the surfacetension of the ultraviolet setting type adhesive already applied to thejoint surfaces of the wedges. After the positioning of the wedges 67 hasbeen accomplished, ultraviolet radiation is applied from the exposed endsurfaces of the wedges 67 to cure the adhesive for gluing and fixation.

It is also possible to arrange one wedge 67 at the center of each sideof the peripheral wall 64e of the fixation frame plate 64. When thefixation frame plate 64 is enlarged, it is possible to minimize theinfluence of the expansion and contraction as a result of temperaturechanges, thereby improving reliability.

In the liquid crystal panel unit 60R, the liquid crystal panel 40R iscovered with and protected by the frame member 61. Further, the framemember 61, holding the liquid crystal panel 40R, is fastened by screwsto the fixation frame plate 64 holding the liquid crystal panel 40R.Thus, the liquid crystal panel 40R is protected, and no external lightis allowed to intrude. When replacing the liquid crystal panel with anew one, it is only necessary to detach the screws. There is no concernthat the surface of the prism composite will be damaged during thereplacing operation.

Since the liquid crystal panel unit 60R of this example includes thepanel frame plate 61 and the fixation frame plate 64, it is possible togenerally reduce weight and thickness. In particular, when furtherreducing the size of the liquid crystal panels 60R, 60G and 60B, aproblem may be encountered. For example, when the thick liquid crystalpanel units are attached to the three surfaces, interference between theliquid crystal panels may occur at the edge portions, thereby making itimpossible to reduce the size of the optical system portion includingthe prism composite 22. In this example, it is possible to form asmall-sized and thin liquid crystal panel unit 60 so that a reduction inthe size of the optical system portion including the prism composite 22is easily realized.

Further, a resin material can be used for the fixation frame plate 64and the first frame plate 62. This reduces weight and enhances theadhesion strength between the prism support plate 33 and the prism unit20. This makes it possible to provide a product resistant to impacts.

In the liquid crystal panel unit 60R of this example, when replacing theliquid crystal panel 40R, it is only necessary to detach the panel frameplate 61 for replacement. In particular, when mounting a new frame plate61, when the panel frame plate 61 is directly attached to the fixationframe plate 64, the focusing position is determined. When the componentsare produced such that the error in the focusing position at the time ofthis mounting is within the permissible depth of focus, there is no needto perform focus adjustment operation at the time of mounting the panelframe plate.

It is also possible to adopt a system in which, after the replacement,several parts of the outer portion of the first frame plate 62 are gluedand fixed to the fixation frame plate without using the screws 66.

As shown in FIG. 9, blind holes 62g may be provided at two diagonallyopposed positions of the four corners of the first fixation frame plate62. By utilizing the blind holes 62g, the first fixation frame plate 62is chucked by an adjusting device to perform positioning with respect tothe face of the prism composite 22. As described above, after theadhesive for gluing and fixing the first frame plate 62 has beencompletely cured, the chucking by the adjusting device is canceled. Thepositioning operation is facilitated by providing such blind holes.

The blind holes 62g for chucking may be in the form of notches providedin the outer periphery of the first frame plate 62. It is also possibleto form an engagement section as a chucking section in the outsideportion which does not interfere with the side wall 64e of the fixationframe plate 64.

As described above, in the projection type display device of theinvention, the light valve can be reliably positioned with respect tothe light synthesizing mechanism so that the deviation amount in pixelmatching is restrained and the focus adjustment can be correctlyconducted. This allows a further level of accuracy to be easilyachieved. In addition, the size of the light synthesizing mechanism canbe reduced in spite of the construction in which the light valve can bereplaced. This contributes to a reduction in the size and weight of theproduct and makes it possible to obtain a product having a highreliability against disturbances. The mounting sections for the lightvalve and the intermediate frame plate or the fixation frame plate arearranged on the vertical wall, whereby a vent portion for cooling air isprovided.

In addition, the light valve arranged on the light incident surface ofthe light synthesizing mechanism is held with its periphery beingprotected by the light valve frame plate. Further, the light valve frameplate holding the light valve is detachably mounted to the fixationframe plate glued and fixed to the light incident surface of the lightsynthesizing mechanism. Thus, in accordance with the present invention,the periphery of the light valve is covered with the light valve frameplate and is protected so that the light valve cannot be damaged duringthe handling process. Further, no external light is allowed to intrude,which would cause a malfunction in the light valve. Further, when amalfunction occurs in the light valve, it is possible to replace onlythe light valve without damaging the surface of the light synthesizingmechanism. This is advantageous from an economical point of view.

While this invention has been described in conjunction with specificembodiments thereof, it is evident that many alternatives, modificationsand variations will be apparent to those skilled in the art.Accordingly, the preferred embodiments of the invention as set forthherein are intended to be illustrative, not limiting. Various changesmay be made without departing from the spirit and scope of the inventionas defined in the following claims.

What is claimed is:
 1. A mounting mechanism for mounting a light valveon a side surface of a prism comprising: a fixation frame plate that isfixed on the side surface of the prism; a light valve frame plate thatholds the light valve, the light valve frame plate being detachablyfixed on the fixation frame plate and the light valve frame plate andthe fixation frame plate being fixed to onto a same side of the prism.2. The mounting mechanism according to claim 1, wherein at least one ofthe light valve frame plate and the fixation frame plate comprises aperipheral wall covering a periphery of the light valve.
 3. The mountingmechanism according to claim 1, further comprising an adjusting memberthat is glued and fixed between the fixation frame plate and the sidesurface of the prism light valve frame plate.
 4. The mounting mechanismaccording to claim 3, wherein the fixation light valve frame platecomprises an adjusting member guide portion.
 5. The mounting mechanismaccording to claim 3, wherein the adjusting member comprises at leastone engagement section utilized when chucking the adjusting member. 6.The mounting mechanism according to claim 3, wherein the adjustingmember is provided proximate a center of opposite side portion of thelight valve frame plate.
 7. The mounting mechanism according to claim 1,wherein the fixation frame plate and the light valve frame platecomprises an engagement section for chucking the plate.
 8. The mountingmechanism according to claim 1, wherein the light valve is a liquidcrystal panel.
 9. A projection type display device of a type projectorwhich modulates a plurality of color beams through a plurality of lightvalves, synthesizes the modulated color beams by a prism, and projects asynthesized beam through a projection lens, the projection type displaydevice projector comprising: a fixation frame plate that is fixed on aside surface of the prism; and a light valve frame plate that holds athe light valve, the light valve frame plate being detachably fixed ononto the fixation frame plate and the light valve frame plate and thefixation frame plate being fixed to a same side of the prism.
 10. Theprojection type display device projector according to claim 9, whereinat least one of the light valve frame plate and the fixation frame platecomprises a peripheral wall covering a periphery of the light valve. 11.The projection type display device projector according to claim 9,further comprising an adjusting member that is glued and fixed betweenthe fixation frame plate and the side surface of the prism light valveframe plate.
 12. The projection type display device projector accordingto claim 11, wherein the fixation light valve frame plate comprises anadjusting member guide portion.
 13. The projection type display deviceprojector according to claim 11, wherein the adjusting member comprisesat least one engagement section utilized when chucking the adjustingmember.
 14. The projection type display device projector according toclaim 11, wherein the adjusting member is provided proximate a center ofopposite side portion of the light valve frame plate.
 15. The projectiontype display device projector according to claim 9, wherein the fixationframe plate and the light valve frame plate comprises an engagementsection for chucking the plate.
 16. The projection type display deviceprojector according to claim 9, wherein the light valve is a liquidcrystal panel.
 17. A mounting mechanism for mounting a light valve on aside surface of a prism comprising: a fixation frame plate that is fixedon the side surface of the prism; a intermediate frame plate that isdetachably fixed on the fixation frame; a light valve frame plate thatholds the light valve plate, the light valve frame plate and thefixation frame plate being fixed to a same side of the prism; and apositioning mechanism positioned proximate to member that is glued andfixed between the intermediate frame plate for positioning and the lightvalve frame plate.
 18. The mounting mechanism according to claim 7 17,further comprising a temporal fixing mechanism that temporarily fixesthe intermediate frame plate and the light valve frame plate.
 19. Themounting mechanism according to claim 18, wherein the temporal fixingmechanism comprises an engagement protrusion formed on one of theintermediate frame plate and the panel frame plate and an engagementhole formed in the other plate.
 20. The mounting mechanism according toclaim 19, wherein the engagement protrusion inserted into the engagementhole is fixed thereto.
 21. The mounting mechanism according to claim 17,wherein the positioning mechanism comprises adjusting parts member foradjusting the position of the light valve.
 22. The mounting mechanismaccording to claim 21, wherein the light valve frame plate furthercomprises an adjusting member guiding mechanism guide portion.
 23. Themounting mechanism according to claim 21, wherein the adjusting partsmember comprises at least one engagement section utilized when chuckingthe adjusting member.
 24. The mounting mechanism according to claim 17,wherein the positioning mechanism is located proximate a center ofopposite side portions of the light valve frame plate.
 25. Theprojection type display device mounting mechanism according to claim 17,wherein the light valve is a liquid crystal panel.
 26. A projection typedisplay device of a type projector which separates a beam from a lightsource into beams of a plurality of colors, modulates each color beamthrough a corresponding light valve in accordance with imageinformation, synthesizes the modulated color beams by light synthesizingprism, and projects the synthesized beam onto a projection surfacethrough a projecting mechanism in an enlarged state, the projection typedisplay device projector comprising: a fixation frame plate fixed to alight incident surface of a the light synthesizing prism; a light valveframe plate for holding the light valve; a fixing mechanism for thatdetachably fixing fixes the light valve frame plate to the fixationframe plate, the light valve frame plate and the fixation frame platebeing fixed to a same side of the prism; and a positioning mechanismpositioned proximate to the fixation frame plate for positioning thelight valve.
 27. A projection type display device of a type projectorwhich separates a beam from a light source into beams of a plurality ofcolors, modulates each color beam through a corresponding light valve inaccordance with image information, synthesizes the modulated color beamsby light synthesizing prism, and projects the synthesized beam onto aprojection surface though a projection mechanism in an enlarged state,the projection type display device projector comprising: a fixationframe plate fixed to a light incident surface of a the lightsynthesizing prism; a light valve frame plate for holding the lightvalve; an intermediate frame plate placed between the fixation frameplate and the light valve frame plate; a fixing mechanism for thatdetachably fixing fixes the light valve frame plate and the intermediateframe plate to the fixation frame plate, the light valve frame plate andthe fixation frame plate being fixed to a same side of the prism; and apositioning mechanism positioned proximate to the intermediate frameplate for positioning the light valve.
 28. A projector which modulates aplurality of color beams, modulates each color beam through a pluralityof light valves, synthesizes the modulated color beams by a prism, andprojects a synthesized beam through a projection lens, the projectorcomprising: a fixation frame plate that is fixed on a side surface ofthe prism; a light valve frame plate that holds the light valve, thelight valve frame plate being detachably fixed onto the fixation frameplate and the light valve frame plate and the fixation frame plate beingfixed to a same side of the prism; a power supply; an input/outputinterface circuit; a video signal processing circuit; a control circuitfor driving and controlling the projector; and an outer casing forhousing the light valves, the prism, the fixation frame plate, the lightvalve frame plate, the power supply, the input/output interface circuit,the video signal processing circuit, and the control circuit.
 29. Theprojector according to claim 28, wherein at least one of the light valveframe plate and the fixation frame plate comprises a peripheral wallcovering a periphery of the light valve.
 30. The projector according toclaim 28, further comprising an adjusting member that is glued and fixedbetween the fixation frame plate and the light valve frame plate. 31.The projector according to claim 30, wherein the light valve frame platecomprises an adjusting member guide portion.
 32. The projector accordingto claim 30, wherein the adjusting member comprises at least oneengagement section utilized when chucking the adjusting member.
 33. Theprojector according to claim 30, wherein the adjusting member isprovided proximate a center of opposite side portion of the light valveframe plate.
 34. The projector according to claim 28, wherein thefixation frame plate and the light valve frame plate comprises anengagement section for chucking the plate.
 35. The projector accordingto claim 28, wherein the light valve is a liquid crystal panel.
 36. Aprojector which separates a beam from a light source into a plurality ofcolor beams, modulates each color beam through a corresponding lightvalve in accordance with image information, synthesizes the modulatedcolor beams by light synthesizing prism, and projects the synthesizedbeam onto a projection surface through a projecting mechanism in anenlarged state, the projector comprising: a fixation frame plate fixedto a light incident surface of the light synthesizing prism; a lightvalve frame plate for holding the light valve; a fixing mechanism thatdetachably fixes the light valve frame plate to the fixation frameplate, the light valve frame plate and the fixation frame plate beingfixed to a same side of the prism; a positioning mechanism positionedproximate to the intermediate frame plate for positioning the lightvalve; a power supply; an input/output interface circuit; a video signalprocessing circuit; a control circuit for driving and controlling theprojector; and an outer causing for housing the light source, the lightvalve, the prism, the fixation frame plate, the light valve frame plate,the fixing mechanism the positioning mechanism, the power supply, theinput/output interface circuit, the video signal processing circuit, andthe control circuit.
 37. A projector which separates a beam from a lightsource into a plurality of color beams, modulates each color beamthrough a corresponding light valve in accordance with imageinformation, synthesizes the modulated color beams by light synthesizingprism, and projects the synthesized beam onto a projection surfacethrough a projecting mechanism in an enlarged state, the projectorcomprising: a fixation frame plate fixed to a light incident surface ofthe light synthesizing prism; a light valve frame plate for holding thelight valve; an intermediate frame plate placed between the fixationframe plate and the light valve frame plate; a fixing mechanism thatdetachably fixes the light valve frame plate to the fixation frameplate, the light valve frame plate and the fixation frame plate beingfixed to a same side of the prism; a positioning mechanism positionedproximate to the intermediate frame plate for positioning the lightvalve; a power supply; an input/output interface circuit; a video signalprocessing circuit; a control circuit for driving and controlling theprojector; and an outer casing for housing the light source, the lightvalve, the light synthesizing prism, the fixation frame plate, the lightvalve frame plate, the intermediate frame plate, the fixing mechanism,the positioning mechanism, the power supply, the input/output interfacecircuit, the video signal processing circuit, and the control circuit.